We discuss several results made possible by accurate SDSS astrometric measurements in a large sky area, with emphasis on asteroids and stellar proper motions obtained by comparing POSS and SDSS. SDSS has observed over 200,000 moving objects in five photometric bands, corresponding to about two orders of magnitude increase over previous multi--color surveys. These data were used to extend the measurement of asteroid size distribution to a smaller size limit, to demonstrate that asteroid dynamical families, defined as clusters in orbital parameter space, also strongly segregate in color space, and to discover a correlation between asteroid age and colors. A preliminary analysis of SDSS-POSS proper motions for ̃1 million M dwarf stars demonstrates that, in the 0.1--1 kpc distance range, the rotational velocity and its dispersion for disk stars increase with the distance from the Galactic plane.
Astrometry in the Age of the Next Generation of Large Telescopes
- Pub Date:
- October 2005
- 9 pages, color figures, presented at the meeting "Astrometry in the Era of the Next Generation of Large Telescopes", Flagstaff, Oct 18-20, 2004